It's an interesting read. I'm especially surprised by the 7.62x39mm. I've seen people advocating this cartridge for increased barrier penetration over 5.45mm and 5.56mm. It seems like it came up short.

I wasn't advising 55 gr. bullets or heavier in a 1:7 twist because of accuracy. Very light bullets in a 1:7 twist rifle can end up spinning so fast that the jacket completely shreds off the bullet due to centrifugal force. Sometimes it looks like a weird flash in front of your muzzle, but the way to tell for sure that the bullet came apart in mid-air is by the odd holes in the target.

An over-stabilized bullet can have issues at longer ranges. Sure, an over-stabilized bullet is a heck of a lot better than an under-stabilized one, but at longer ranges a 50 gr. bullet is going to work better in a 1:8 or 1:9 rifle than in a 1:7.

At home-defense ranges over-stabilization is isn't an issue, but the jacket separating in mid-air due to the bullet spinning too fast can be a problem. That's why I advised that if you have a 1:7 barrel you should test any home defense load that has a bullet 50 gr. and below, because jacket separation has been know to happen in 1:7 rifles using those bullets.

It's definitely not a myth; jacket separation happens. Does it happen every time you shoot light loads in a 1:7? Of course not; but it still happens, and the best way to avoid it happening is to use bullets of an appropriate weight. Also, over-stabilization effects accuracy, especially at longer ranges. Is it as bad as an under-stabilized bullet? No. You might not even notice the difference at shorter ranges. But shooting very light bullets in a 1:7 is not ideal.

Agree. I know of at least one rifle, a 1:7 16" barrel AR-15 that can not shoot 45 grain ammo. The bullets fall apart at about 30 yards. M-193 55 grain is OK, but that particular gun is most accurate with 60+ grain projectiles.

It's definitely not a myth; jacket separation happens. Does it happen every time you shoot light loads in a 1:7?

What are you calling a "light" load? I have seen this argument used to suggest 55gr is a bad choice for 1:7 twists but in tens of thousands of rounds downrange, I've never seen any 55gr come apart due to twist rate. I've read people report problems with 36gr varmint grenades, which are really questionable for defense or large mammals.

It seems to me that any round that has a realistic probability of spinning apart in a 1:7 .223 is probably not a good choice for self-defense out of any twist rate.

I'm talking about 45 grain and lower. I'd worry about 50 grain coming apart also, but I admit I've never seen it happen. 55 grain is fine in a 1:7 but you will generally be more accurate at longer ranges with a 1:8 or 1:9 using those bullets.

I'd argue that the irregular nature of the jacket on most 55gr ammo (99% of it being cheap blasting ammo) plays a bigger role in accuracy differences than the weight. On the other hand Hornady 55gr TAP and Training ammo has been great out of 1:7 and 1:8 barrels for me.

It's my understanding you only notice the over stabilization of bullets at the longer ranges of that particular bullet . If a bullet is spinning to fast as it starts slowing down the tip wants to stay up and not point down in the same plain the bullet is traveling or in the same angle as the bullets arc . I just happen to be talking about this with a friend the other day that knows more about this stuff then I do . It seemed to make sense to me .

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